From: "Michal Koutný" <mkoutny@suse.com>
To: Noah Feldt <noah@feldt.systems>
Cc: Tejun Heo <tj@kernel.org>,
cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
N.Feldt@mittwald.de, carnil@debian.org, dschatzberg@meta.com,
hannes@cmpxchg.org, peterz@infradead.org,
stable@vger.kernel.org
Subject: Re: [PATCH v2] cgroup: Avoid iteration of dying tasks with zero refcount
Date: Fri, 11 Sep 2026 18:11:42 +0200 [thread overview]
Message-ID: <aqQlowpkYrTaVmid@localhost.localdomain> (raw)
In-Reply-To: <aqAtv3WVn51LN3E8@localhost.localdomain>
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On Tue, Sep 08, 2026 at 05:55:45PM +0200, Michal Koutný <mkoutny@suse.com> wrote:
> Though, the fix loses a bit of elegance. Hm, thinking...
So, it occurs to me that the ->live based predicate from v2 might break
CSS_TASK_ITER_WITH_DEAD callers (zombies they asked for would be
skipped).
We need to distinguish between (both on dying_tasks list):
- regular zombies waiting to be reaped and
- RCU remnant tasks that are going to be free'd.
IIUC these two are split on the ->usage count. (Correct me if I'm
wrong.)
I'm starting to like the tryget_task_struct() approach from v1 again.
Michal
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next prev parent reply other threads:[~2026-09-11 16:11 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-07 19:27 [PATCH v2] cgroup: Avoid iteration of dying tasks with zero refcount Noah Feldt
2026-09-08 15:55 ` Michal Koutný
2026-09-11 16:11 ` Michal Koutný [this message]
2026-09-11 16:57 ` Tejun Heo
-- strict thread matches above, loose matches on Subject: below --
2026-09-07 17:03 Michal Koutný
2026-09-07 17:07 ` Michal Koutný
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